Study on Haploid Inducing and Its Meiotic Abnormality in Maize

The haploid-inducing line Stock 6 was used to produce haploid maize and expected to obtain maize haploid plants successfully. The detailed meiotic studies on selected haploid maize (n = x = 10) were conducted. Cytogenetic analysis revealed a high frequency of meiotic abnormality occurred in both meiosis I and meiosis II. During the prophase I, univalents were common configurations, and there were bivalents or trivalents in some pollen mother cells, however, a few cells containing five bivalents were also observed. After prophase I, chromosomes did not congregate in a single metaphase plate but they were scattered in the cytoplasm. At anaphase I, the chromosome distribution was highly irregular with almost all possible combinations. In some cells, chromosomes were grouped into the three or four masses and several spindles appeared. At the tetrad stage of meiosis II, cytokinesis splitting abnormality occurred, and a variety of diad, triad, tetrad, pentad, hexad, as well as decury microspores were easily observed. As a consequence of abnormalities of the two meiotic stages, various microspores and the pollen grains with different size were formed, and its pollen grains were almost completely sterile.